Hi,
Your concerns are valid and are your knowledge is pretty accurate. Stage 4 disease means metastatic cancer.
My simplest interpretation is that there may be some miscommunication somewhere. Stage 4 may have actually meant T4 (a coding system for the primary T meaning Tumor, referring to the primary tumor).
There are some rare varieties of Breast cancer such as inflammatory breast cancer that tends to grow not in masses but over surfaces. Inflammatory breast cancers are classified as T4. A good many of them are also too extensive to preclude a curative attempt at surgery, and may thus receive chemotherapy, radiation, or both.
The statement regarding “cancer cells spreading” due to interventions like surgery would depend on the surgery. If the surgery is an attempt at cure, meaning the entire tumor is removed with a clear margin of normal tissue– then this kind of surgery will not promote cancer spread. If the case is extensive, the surgery may leave residual tumor. Lines where incisions were made may have overlaps with residual disease. Cancer must break through barriers prior to invading. A surgical incision cuts through barriers already , thereby facilitating cancer spread.
I think it would be best to review the information with your friend, if possible with the doctor present to clarify some misconceptions.
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